60 ERIK A : SON STENSIO 
considerably dorsally of the basis cranii. The explanation of this seems to be that the 
basal parts of the cranium have increased greatly in height at this place, a fact that 
may possibly, at any rate to some extent, be connected with the development of the 
basal canal m described above, which, for reasons to be given later, perhaps ought 
to be interpreted as a myodome. 
In Dictyonosteus there is also apparently a basipterygoid process (Stensio, 1918 c, 
Bp, PI. IV, fig. 3 , PI. V, fig. 1, PI. VI). There, however, it seems to occupy a more 
primitive position, as it issues farther ventrally on the lateral side of the neurocranium 
than in the Coelacanthids, without, however, being situated at the cranial basis itself. 
Another primitive feature in Dictyonosteus is that the cranial cavity over the part of 
the sphenoid that corresponds to the basisphenoid corpus is considerably higher in a 
vertical direction than in Coelacanthids and that consequently the basal parts of the 
cranium in this region are comparatively lower. 
While the ramus maxillaris and ramus mandibularis trigemini in IP. sinuosa, after 
their exit from the cranial cavity, presumably passed behind the basipterygoid process 
or over its posterior part in a lateral direction, the nervus ophthalmicus lateralis must 
have crossed over this process in a forward direction close to the lateral wall of the 
brain-case. If my interpretation of the process in question is correct, the jugular vein 
(v. capitis lateralis) should also have proceeded in a similar way to that of the last 
mentioned nerve (cf. Allis, 1909 a, p. 44, pp. i 83 —208; 1914 a, pp. 225—253; 1914b, 
pp. 625—637). That the relations of the trigeminal branches in the Coelacanthids have 
agreed in the main with those in Dictyonosteus seems to be evident from my description 
of this form and the reproductions published in connection with it (Stensio, 1918 c, 
PL IV, V, VI). Ramus maxillaris and r. mandibularis must thus in Dictyonosteus have 
penetrated the cranial wall postero-dorsally of the basipterygoid process at one part, 
which is not, however, preserved. The nervus ophthalmicus lateralis must have had 
its exit at about the same place and after that in its forward course been situated 
for some distance in a rather short canal in the lateral wall of the pars alisphenoidea 
of the sphenoid, not for below the posterior part of the frontals (cf. Axelia). 
With regard to n. facialis it may possibly be thought that in Wimania sinuosa it was 
transmitted together with the trigeminal branches (cf. Gaupp, 1911, p. 421), but this view- 
does not seem probable. On the other hand it might also possibly have had its exit 
behind the process fj. The furrow si, described above on the prootico-opisthotic 
medially of the process just mentioned has, however, such a forward, downward and 
lateral direction that at least the ramus palatinus must probably have been in relation 
to it. A comparison with Lepidosiren (Bridge, 1898, pp. 348 — 349) and Eryops (Abel, 
1919, fig. 188; Huene, igi 3 , pp. 320— 322; Watson, 1916, pp. 612—618; 1919, pp. 22—29) 
suggests that in these forms the nerve as a whole has had its exit at the corresponding 
place. If this is correct, it thus has in IT. sinuosa, with the present state of preservation 
of the cranium, its foramen in such a position (VII, text figs. 19, 20) that it is bounded 
anteriorly by the basisphenoid corpus, posteriorly by the process fj on the prootico- 
opisthotic, and ventrally by the anterior part of the corpus of the latter bone. 
The possible position of the foramen nervi glossopharyngei has already been 
mentioned. It must be expressly stated that in this case, however, we are only con- 
